Injury to the Ulnar nerve at the wrist causes paralysis of-

Okay, let's tackle this question step by step. The question is about the injury to the ulnar nerve at the wrist and which muscles it would paralyze. First, I need to recall the anatomy of the ulnar nerve. The ulnar nerve is one of the major nerves in the arm, running from the neck down to the hand. It branches off from the brachial plexus and is responsible for motor and sensory functions in parts of the hand.

At the wrist level, the ulnar nerve is particularly vulnerable because it passes through the Guyon's canal. Injuries here can affect the muscles it innervates. The ulnar nerve innervates several muscles in the forearm and hand. The main muscles involved are the flexor carpi ulnaris, the medial half of the flexor digitorum profundus, and all the intrinsic muscles of the hand except the thenar muscles and the lateral two lumbricals.

So, when there's an injury at the wrist, the muscles that are paralyzed would be those supplied by the ulnar nerve distal to the injury site. The intrinsic hand muscles include the hypothenar muscles, interossei, adductor pollicis, and the medial half of the flexor digitorum profundus. The thenar muscles (abductor pollicis brevis, flexor pollicis brevis, and opponens pollicis) are innervated by the median nerve, so they wouldn't be affected here. The lateral two lumbricals are also median nerve innervated.

Looking at the options, the correct answer would be the muscles that are specifically supplied by the ulnar nerve. The options are not provided, but common distractors might include muscles like the flexor carpi radialis (innervated by the median nerve), the extensor carpi ulnaris (radial nerve), or the brachioradialis (radial nerve). Also, muscles like the flexor digitorum superficialis are innervated by the median nerve, so they wouldn't be affected by an ulnar nerve injury at the wrist.

The clinical pearl here is to remember that ulnar nerve injuries at the wrist affect the intrinsic hand muscles and the medial half of the FDP. The "claw hand" deformity is a classic sign of ulnar nerve damage, where the ring and little fingers are hyperextended at the metacarpophalangeal joints and flexed at the interphalangeal joints. This occurs due to the unopposed action of the lumbricals on the affected fingers.

**Core Concept**
The ulnar nerve innervates intrinsic hand muscles and the medial half of the flexor digitorum profundus (FDP). Injury at the wrist (Guyon's canal) disrupts these muscles, sparing the thenar muscles and lateral lumbricals (median nerve territory).

**Why the Correct Answer is Right**
The ulnar nerve at the wrist supplies:
1. **Hypothenar muscles** (abductor digiti minimi, flexor digiti minimi, and opponens digiti minimi).
2. **Interossei** (dorsal and palmar) and **lumbricals** (medial three).
3. **Adductor pollicis** and **medial half of the FDP**.
Paralysis of

✓ Correct Answer: C. Adduction of the thumb